Manufacture of arseno compound of the pyrazolone series



Patented Sept. 9, 1924.

UNITED STATES PATENT? OFFICE.

KARL STREITWOLF, OF HOCH ST-ON-THE-MAI N, GERMANY, ASSIGNOR TO HERMANN A.

METZ, F NEW.YORK, N. Y. j

MANUFACTURE OF ARSENO' COMPOUND OF THE PYRAZOLO NTE SERIES.

Io Drawing.

nently valuable properties because they are of slight toxicity and yet have a strong spirillocide action. They are applied in affections caused by spirilli in' the. form of their stable alkali salts, which are readily soluble with neutral reaction and also keep well when dissolved.

The'process for preparin the new compounds consists in -introducing acid atomic groups into the arseno-di (4-amino-2.3-

dialkyl-l-aryl-5-pyrazolone) by means of known reactions. They are yellow powders which are insoluble in water and alcohol, but readily soluble in diluted mineral acids and alkalies or alkali carbonates. When heated with acids they are decomposed.

A particular method of carrying out the process consists in causing aldehydesulfoxylates to act upon 4-nitrosoor 4-nitro-1- phenyl-2.3-dialkyl-5-pyrazolonarsinic acids instead of starting from a finished aminoarseno compound. When working after this method the transformation of the arsinic acid group into the arseno group, the reduction of the nitrosoor nitro group into the amino group and the introduction of the alkylenesulfoxyl residue into the amino group are effected in one single operation.

Examples.

1. 1- (phenyl-p-arsinic acid) -3-methyl-5- chloropyrazol 207,5 gr. of l-p-aminophenyl- 3-methyl-5-chloropyrazol are dissolved in 1,5 litresv of water while adding 200 com. of concentrated hydrochloric acld, and this solution,isdiazotized by means of nitrite. h v

2.3-dimethyl-5-pyra'zolone: 312gr. of pyra- The diazo Solution thus obtained is treated in the known mannerfwi th an arsenite accordin "to" the processes described in'Germanv atents FNos. 250264, 268172 c or 254C092. After acidifying'the' 1'- (phenyl-pa out 192195 5-pyrazolone Application filed October 23,1920. Serial No. 419,158.

' arsinic acid) -3-methyl-5-chloropyrazol is precipitated. It can be recrystallized from s irit. When quickly heated it melts at C. with formation of anhydride. After elimination of the water it solidifies again. It decomposes completely only at a temperature above 290 C.

2. 1- (phenyl-p-arslnic acid)-3-methyl-5- gyrazolone: 217 gr. of arsanilic acid are lazotized in known manner and this diazo solution is introduced ina solution of 500 gr. of stannous chloride in 1000 ccm. of concentrated hydrochloric acid. To the solution thus obtained and which contains phenylhydrazinarsinic acid, are added all at once 156 gr. of acetoacetic ester and the whole is stirred for 12 hours. During the reaction some arsenopyrazolone separates which is removed by filtration.

The solution is then diluted with water until there is no further precipitation, and after filtration the precipitated tin double salt is washedwith water. In order to free the latter from any tin it isdissolved in sodium carbonate while heating and from the filtered ofi' solution the l-(phenyl-parsinic acid)-3-methyl-5-pyrazolone is precipitated by acidification and the product thus obtained is filtered ofl:', washed and dried. I It is difiicultly soluble in cold water, .and can be recrystallized fromhot water.

It is readily soluble in alkalies, and forms a yellow nitroso compound.

. 3. l-(phenyl-p-arsinic acid) 2.3-dimethyl- 500 arsinic acid) -3-methyl-5-'chlorpyrazol are heated for 6 hours with 400 gr. of dimethyl sulfate to 120 C. The reaction mass is dissolved with 1 kg. of calcined sodium carbonate in 4 liters of water and this solutionis heated for 12 hours to 95 C. The solution is then carefully acidified and the precipitated l-(phenyl-p-arsinic acid) -2.3-

dimethyl-5-pyrazolone is filtered ofi. It can be recrystallized from water and is readily soluble in'diluted acids and alkalies.

The same compound can be produced from pyrazolone-ar sinic acid (as per example 2) by methylation.

4.- 4-nitroso-1- (,phenyl-p-arsinic acid) bonate. There are thenadded 70 gr. of

of 1- (phenyl-pand further added all at once the equivalent quantity (1 -molecular proportion) of J diluted sulfuric acid. The thus obtained' bluish-green nitroso compound separates and can be filtered off. It is not stable and can be kept only for a short time. I 1

5. Arseno compound from 4-mtr0so-1- (phenyl-p-arsinic acid) -2.3-dimethyl-5-pyrazolone: 125 gr. of the nitroso compoun obtainable according to example 4 are introduced while stirring'into a solution of 1200 gr. of hydrosulfite, dissolved in 5000 liters of water. The solution thus obtained is heated for 2 hours to 60-65 0., the yellow precipitate is filtered oil? and washed with water. In order to obtain it in a pure state, the base thus obtained is dissolved in methyl alcohol and hydrochloric acid and from the solution the hydrochlorate is precipitated with ether. It forms yellow crystals which are readily soluble in methyl alcohol and water.

6. p-arseno-di (1-phenyl-2.3-d1methyl-4- amino-5-pyrazolone) monoacetic acid: 12,54 gr. of chloride of p-arseno-di (l-plienyl-iamino-2.3-dimethyl-5-pyrazolone) are dissolved in 100 com; of water, neutralized with caustic soda lye of 15% strength and there are then added 14 gr. of bromacetic acid, dissolved in 30 gnof water.- The whole is heated for a short time to about 60 0. diluted with water and a solution of sodium carbonate added thereto. The undissolved portion is filtered ofi and the glycine-arseno compound is precipitated from the solution by means of. acetic acid. It constitutes a yellowish powder, diflicultly soluble in water and insoluble in alcohol. It dissolves in hydrochloric acid, caustic soda lye and sodium carbonate and forms readily-soluble yellow'alkali salts.

If in this example a larger excess of bromacetic acid is used, the diglycine which is similar to the monoglycine, is obtained.

7. parseno-di (1-phenyl-2.3-dimethyl-4- amino-5-pyrazolone) monomethylenesulfoxylic acid: 95 gr. of chloride of p-arseno-di- 1-' henyl-2.3dimethyli-amino 5 pyrazolone are dissolved in 250 ccm.'of methyl al-. cohol and 100 com. of water and to this solution are added 38 of formaldehydesulfoxylate, dissolved m 100 com. of water. The whole is stirred for a quarter of an hour. and there are then added a sodium carbonate solutionand water until the mix- 'ture is almost entirely dissolved. The solu-.

tion is then filtered and the arsenosulfoxylic .acid is carefully precipitated by adding di-' lute hydrochloric acid. It forms a yellowish powder, difiicultly soluble in water and insoluble in alcohol, but which dissolves in hydi'ochloric acid, caustic soda lye and sodium, carbonate forming readily-soluble yel- 0w. alkali s d f hydrochloric acid. As soon as the When using a larger excess of formaldehydesulfoxylate in this exam Ie, the dimethylenesulfoxylic acid is prodhced.

8. 15.6 gr. of 1- (phenyl-p-arsinic acid)- 2.3-dimethyl-5-pyrazolone are dissolved with com. of normal caustic soda lye and mixed with 3,5 gr. ofisodium nitrite in 10 com. of water. There are then added 50 "cc.

nitroso compound has become entirely crystallized, gr. of formaldehydesulfoxylate dissolved in 150 com. of water are added. lhus a clear yellow solution is produced which, on addition of 25 com. of hydrochloric acid, is heated for a short time on the water bath. 1 After precipitation there is immediately added some ice whereupon the isolated sulfoxylic acid is filtered 011' and well washed.- It forms a yellow powderdwhich is soluble in alkalies and strong ac1 Having now described my invention, what I claim is: 1

1. As a. new process, the reparation of new arseno compounds of t e pyrazolone series, which consists in introducing acid atomic groups into the amino group of the ars'eno-di (1-aryl-2.3dialkyl-4-amino-5-pyi'azolone).

2. As a new process, the preparation of new arseno compounds of the pyrazolone series, which comprises reacting upon a p-arseno di (1 phenyl-4-amino-2;3-dimethyl-5- pyrazolone with a compound comprising a sulfoxyl residue. I

3. As a new process, the preparation of new arseno compounds of the pyrazolone series which consists in efiecting the introduction of the sulfoxyl group into-the amino group simultaneously with the preparation .of the arseno amino pyrazolones in one operation by causing aldehydesulfoxylate to no act upon -nitrosoor 4-nitro-1-aryl-2.3-di-' alkyl-5-pyrazolone-arsinic acids.

4. As new products, the compounds of the arseno-di- 1-ary1-2.3-d1ialkyl-45-amino-5 pyragplo'ne) corresponding to the general form a:

compounds being, when crystallized, yellow crystalline powders and forming, when combined with alkalies, yellow alkali salts readily soluble in water. i

5. As new products, the compounds of arseno di- (1-aryl-2.3-dial1ky1-4Famino-5-pyra- 5-pyrazolone) containing in each of the am- 10 zolones) containing a sulfoxyl group in at ino groups of the-pyrazolone residues a sulleast one of the amino groups of a pyrazo-- f lone residue, being, when crystallized, yellow constitutes a yellow crystalline powder form- 5 crystalline powders which form, when coming,.when combined with alkalies, yellow albined with alkalies, yellow alkali salts which kali salts readily soluble in water. 15 are readily soluble in water. In testimony whereof, I afiix my signa- 6. As a new product, the comfiound of the ture.

l-arseno-di-(1-phenyl-2.3-dimet yl-4 amino- DR. KARL STREVITWOLF.

oxylgroup and which, when crystallized, 

